Kanako's wisdom tooth pain worsened, forcing her to undergo surgery and hospitalization. Her husband, Yukihiro, was left alone at home, so Kanako's mother, Sayaka, decided to stay at their house for a while to take care of things. Yukihiro felt slightly uneasy about spending time with his stepmother again after so long, while Sayaka felt nervous being around a younger man. One day, Sayaka accidentally caught a glimpse of Yukihiro's crotch. In that instant, both panicked, setting off an unexpected chain of events. Through this unforeseen incident, their relationship gradually grows deeper.